The present invention relates to a dryer, a dryer assembly and a drying method that are applied for drying a to-be-dried object using far infrared radiation.
There has conventionally been known a dryer using far infrared radiation. A far infrared radiator used in the dryer is a metal pipe whose outer surface is provided with a far infrared layer, ceramics and the like. In such a dryer, hot air that is heated by a far infrared radiator is circulated in a drying furnace. Such a hot air circulation method has generally been adopted in a drying furnace.
Especially, in a case where a to-be-dried object is a thin film board made from an epoxy resin on which acrylic resin is coated, there have arisen problems that the to-be-dried object is heated to a high temperature and as a result, the resin is burned or the board is deformed when the to-be-dried object is dried using far infrared radiation having the most suitable wavelength for the to-be-dried object. Therefore, a wavelength range of the far infrared radiation has been shifted to the longer wave side from the wavelength corresponding to the maximum absorbance and thereby, a drying time becomes longer and a quality of the product is problematic.
Besides, impurities included in the dusts, a solvent in resin and the like, generated from a to-be-dried object in a drying process, is mixed into hot air. When the hot air containing such materials is circulated in a drying furnace, the materials attach to resist on a print board and cause inconveniences on the drying process. For example, minute sized impurities in the hot air stick to the surface of the resist, which produce a cause for electric short in the wiring. On the other hand, harmful gases and the like generated in a drying process of resin or the like are released into the atmosphere from the drying furnace, which exerts an adverse influence on the environment.
The present invention has been made in order to solve the above problems and can irradiate a to-be-dried object with far infrared radiation having an optimal wavelength in an effective and efficient manner. It is accordingly an object of the present invention to provide a dryer and a drying method that can reduce a time to be required for drying without deformation of a to-be-dried object regardless of a kind and a thickness of the to-be-dried object and can thereby achieve an excellent dried state.
It is another object to provide a dryer and a drying method in which only clean hot air is supplied in a manner such that neither of impurities in dusts, solvent in resin and the like generated from a to-be-dried object in a drying process reaches a surface of a print board or the like, and thereby, drying of precision parts can be effected in a good yield, and in addition, in which special consideration is given to environment so that neither of harmful gas or the like generated in a drying process of resin or the like is released into the air from the drying furnace.
The disclosure of the invention
A dryer comprises:
a far infrared radiator that emits far infrared radiation optimal for drying a to-be-dried object;
a drying chamber in which far infrared radiation emitted by the far infrared radiator is directed to the to-be-dried object to dry the to-be-dried object;
a plenum chamber for preparing a downflow of hot air toward the drying chamber;
a frame to which a plurality of the far infrared radiators are mounted and which is provided with an opening for jetting the hot air that flows down from the plenum chamber toward the drying chamber;
an elevating device for varying a distance between the to-be-dried object and the far infrared radiators;
a hot air closed circulation path for circulating the hot air that is heated up by heat generated from the far infrared radiators; and
a control device for controlling a temperature in the drying chamber, an irradiation time of far infrared radiation, a surface temperature of the far infrared radiator and a distance between the far infrared radiator and the to-be-dried object.
A dryer comprises:
a far infrared radiator that emits far infrared radiation optimal for drying a to-be-dried object;
a drying chamber in which far infrared radiation emitted by the far infrared radiator is directed to the to-be-dried object to dry the to-be-dried object;
a plenum chamber for preparing a downflow of hot air toward the drying chamber;
a frame to which a plurality of the far infrared radiators are mounted and which is provided with an opening for jetting the hot air that flows down from the plenum chamber toward the drying chamber;
an elevating device for moving the plenum chamber and the plurality of far infrared radiators, as one body, upward or downward;
a hot air closed circulation path for circulating the hot air that is heated up by heat generated from the far infrared radiators; and
a control device for controlling a temperature in the drying chamber, an irradiation time of far infrared radiation, a surface temperature of the far infrared radiator and a distance between the far infrared radiator and the to-be-dried object.
A dryer comprises:
a far infrared radiator that emits far infrared radiation optimal for drying a to-be-dried object;
a drying chamber in which far infrared radiation emitted by the far infrared radiator is directed to the to-be-dried object to dry the to-be-dried object;
a plenum chamber for preparing a downflow of hot air toward the drying chamber;
an enclosure for enclosing the plenum chamber and the far infrared radiator;
a frame to which a plurality of the far infrared radiators are mounted and which is provided with an opening for jetting the hot air that flows down from the plenum chamber toward the drying chamber;
an elevating device for varying a distance between the to-be-dried object and the far infrared radiators;
a hot air closed circulation path for circulating the hot air that is heated up by heat generated from the far infrared radiator; and
a control device for controlling a temperature in the drying chamber, an irradiation time of far infrared radiation, a surface temperature of the far infrared radiator and a distance between the far infrared radiator and the to-be-dried object.
A dryer comprises:
a far infrared radiator that emits far infrared radiation optimal for drying a to-be-dried object;
a drying chamber in which far infrared radiation emitted by the far infrared radiator is directed to the to-be-dried object to dry the to-be-dried object;
a reflecting plate disposed on one side of the to-be-dried object and an insulating material disposed on the other side, wherein the reflecting plate is opposed to the far infrared radiator;
an elevating device for varying a distance between the to-be-dried object and the far infrared radiators;
a first exhaust duct for discharging a gasified solvent or the like from the to-be-dried object in the drying chamber to the atmosphere;
a second exhaust duct for discharging hot air that circulates in the drying chamber;
a hot air closed circulation path for circulating the hot air that is heated up by heat generated from the far infrared radiator; and
a control device for controlling a temperature in the drying chamber, an irradiation time of far infrared radiation, a surface temperature of the far infrared radiator and a distance between the far infrared radiator and the to-be-dried object.
In the dryer,the far infrared radiator includes: a far infrared radiation layer provided on a surface of a curved metal plate; a heating device for heating the metal plate; and a holding/shaping plate for holding the metal plate in a curved shape and/or making the metal plate assume a curved shape.
In the dryer, the hot air closed circulation path is a closed path through which the hot air circulates from the drying chamber through the plenum chamber again to the drying chamber.
The dryer,further comprises a gas molecule decomposition device that is provided in the hot air closed circulation path for cleaning the hot air that flows down from the plenum chamber.
In the dryer,the gas molecule decomposition device is located between the plenum chamber and the far infrared radiator at a site close to the far infrared radiators.
In the dryer,the gas molecule decomposition device has a radical reaction chamber in the enclosure for removing a gas molecule included in the hot air by a radical reaction.
In the dryer,the gas molecule decomposition device is located at a position downstream from the drying chamber.
The dryer, further comprises: a catalyst device and a filter device in the hot air closed circulation path in addition to the gas molecule decomposition device.
In the dryer,the filter device is provided in the plenum chamber.
In the dryer,the gas molecule decomposition device includes a heating device, a heat exchanger or a heat accumulator.
In the dryer, the heat accumulator has a structure in which a plurality of pipes made of a material with good heat conductivity are arranged at predetermined intervals.
In the dryer, the far infrared radiator emits far infrared radiation from above and below the to-be-dried object.
In the dryer, the far infrared radiator is arranged above or below the to-be-dried object and a reflecting plate that reflects far infrared radiation emitted from the far infrared radiator is disposed below or above the to-be-dried object.
In the dryer, the drying chamber includes an enclosure comprising a reflecting plate disposed on one side of the to-be-dried object and an insulating material disposed on the other side of the to-be-dried object.
In the dryer, an interior of the enclosure constitutes a radical reaction chamber.
The dryer, further comprises: an exhaust path for discharging the hot air that is circulating in the hot air closed circulation path into the atmosphere; and a removal device provided in the exhaust path for preventing impurities in the hot air from being discharged into the atmosphere.
In the dryer, the exhaust path comprises: a first exhaust duct for discharging a gasified solvent or the like from the to-be-dried object in the drying chamber into the atmosphere; and a second exhaust duct for discharging the hot air that is circulating in the drying chamber to the atmosphere.
In the dryer, a surface temperature of the to-be-dried object is set to a predetermined temperature through control by the control device of at least one of the parameters including a temperature in the drying chamber, a surface temperature of the far infrared radiator, an irradiation time of far infrared radiation and distance between the far infrared radiator and the to-be-dried object.
In the dryer, the control device controls at least one of parameters including a temperature in a drying chamber, a surface temperature of the far infrared radiator, an irradiation time of far infrared radiation and a distance between the far infrared radiator and the to-be-dried object so that no deformation of the to-be-dried object occurs.
In the dryer, the to-be-dried object includes a thin board made of acrylic resin and a surface temperature of the board is set in the range of from about 50xc2x0 C. to about 90xc2x0 C.
In the dryer, the to-be-dried object includes a thin board made of polycarbonate resin and a surface temperature of the board is set in the range of from about 70xc2x0 C. to about 75xc2x0 C.
In the dryer, the to-be-dried object includes a thin board made of epoxy resin and a surface temperature of the board is set in the range of from about 120xc2x0 C. to about 145xc2x0 C.
In the dryer, the to-be-dried object includes a thin board made of aluminum and a surface temperature of the board is set in the range of from about 100xc2x0 C. to about 175xc2x0 C.
The dryer assembly comprises a plurality of the dryers, each as a unit, parameters in each dryer including a temperature in a drying chamber, an irradiation time of far infrared radiation, a surface temperature of the far infrared radiator and a distance between the far infrared radiator and the to-be-dried object are independently controlled.
In the dryer assembly ,in at least one of the parameters in each dryer including a temperature in a drying chamber, an irradiation time of far infrared radiation, a surface temperature of the far infrared radiator and a distance between the far infrared radiators and the to-be-dried object is differently set from the other dryers.
In the dryer assembly ,a temperature in a drying chamber is set to the lowest on the inlet side of the to-be-dried objects in a dryer.
In the dryer assembly, the dryer uses insulating material for a frame.
The dryer assembly comprises an ultraviolet radiator for irradiating the to-be-dried object with ultraviolet after the to-be-dried object is irradiated with far infrared radiation from the far infrared radiator.
In the dryer assembly,an irradiation dose of ultraviolet emitted from the ultraviolet radiator is in the range of from about 300 to about 600 mJ/cm2.
The dryer assembly comprises an ultraviolet radiator for irradiating each to-be-dried object with ultraviolet before the to-be-dried object is irradiated with far infrared radiation from the far infrared radiator.
The dryer assembly comprising a plurality of the dryer comprises a microwave radiator for irradiating the to-be-dried object with microwave before the to-be-dried object is irradiated with far infrared radiation from the far infrared radiator.
The dryer assembly further comprises transport means for transporting the to-be-dried object between the plurality of dryers, between the dryer and the ultraviolet radiator, or between the dryer and the microwave radiator.
In the dryer assembly, transport means is provide d with transmission means for transmitting a microwave, far infrared radiation and ultraviolet.
A drying method comprises:
a step of changing a wavelength range of far infrared radiation in order to supply far infrared radiation optimal for drying a to-be-dried object by changing a surface temperature of a metal plate from which the far infrared radiation is emitted;
a step of setting a surface temperature for setting a surface temperature of the to-be-dried object to a predetermined temperature by controlling a distance between a far infrared radiator and the to-be-dried object;
a step of irradiating the to-be-dried object with far infrared radiation of the predetermined wavelength from the far infrared radiator; and
a step of supplying hot air heated up by using heat generated from the far infrared radiator to the to-be-dried object through a hot air closed circulation path.
A drying method comprises:
a step of changing a wavelength range of far infrared radiation in order to supply far infrared radiation optimal for drying a to-be-dried object by changing a surface temperature of a metal plate from which the far infrared radiation is emitted;
a step of setting a surface temperature for setting a surface temperature of the to-be-dried object to a predetermined temperature by controlling a distance between a far infrared radiator and the to-be-dried object;
a step of irradiating the to-be-dried object with far infrared radiation of the predetermined wavelength from the far infrared radiator;
a step of supplying hot air heated up by using heat generated from the far infrared radiator to the to-be-dried object through a hot air closed circulation path; and
a step of irradiating the to-be-dried object with ultraviolet after the to-be-dried object is irradiated with far infrared radiation.
In the drying method ,an irradiation dose of ultraviolet emitted from the ultraviolet radiator is in the range of from about 300 to about 600 mJ/cm2.
A drying method comprises:
a step of irradiating a to-be-dried object with ultraviolet;
a step of changing a wavelength range of far infrared radiation in order to supply far infrared radiation optimal for drying the to-be-dried object by changing a surface temperature of a metal plate from which the far infrared radiation is emitted;
a step of setting a surface temperature for setting a surface temperature of the to-be-dried object to a predetermined temperature by controlling a distance between a far infrared radiator and the to-be-dried object;
a step of irradiating the to-be-dried object with far infrared radiation of the predetermined wavelength from the far infrared radiator; and
a step of supplying hot air heated up by using heat generated from the far infrared radiator to the to-be-dried object through a hot air closed circulation path.
A drying method comprises:
a step of irradiating the to-be-dried object with a microwave;
a step of changing a wavelength range of far infrared radiation in order to supply far infrared radiation optimal for drying a to-be-dried object by changing a surface temperature of a metal plate from which the far infrared radiation is emitted;
a step of setting a surface temperature for setting a surface temperature of the to-be-dried object to a predetermined temperature by controlling a distance between a far infrared radiator and the to-be-dried object;
a step of irradiating the to-be-dried object with far infrared radiation of the predetermined wavelength from the far infrared radiator; and
a step of supplying hot air heated up by using heat generated from the far infrared radiator to the to-be-dried object through a hot air closed circulation path.
A drying method comprises:
a step of changing a wavelength range of far infrared radiation in order to supply far infrared radiation optimal for drying a to-be-dried object by changing a surface temperature of a metal plate from which the far infrared radiation is emitted;
a step of setting a surface temperature for setting a surface temperature of the to-be-dried object to a predetermined temperature by controlling a distance between a far infrared radiator and the to-be-dried object;
a step of supplying hot air heated up by using heat generated from the far infrared radiator to the to-be-dried object through a hot air closed circulation path;
a step of irradiating the to-be-dried object with far infrared radiation of the predetermined wavelength from the far infrared radiator; and
a step of supplying hot air heated up by using heat produced from the far infrared radiator after cleaning the hot air to the to-be-dried object through a hot air closed circulation path. 43. In the drying method according to any of claims 37, 38, 40, 41or 42, the hot air supplied to the to-be-dried object is prepared from a plenum state as a downflow.
In the drying method,the far infrared radiation of a wavelength in the range of from about 3 xcexcm to about 6 xcexcm corresponding to the maximum absorbance inherent to the to-be-dried object is selected in the step of changing the wavelength range of far infrared radiation.
The drying method, further comprises a step of cleaning for causing a radical reaction by gas decomposition of impurities in the hot air that circulates in the hot air closed circulation path.